Busbars: Overcoming Overcurrent at Copper Joints
In the fast-growing new energy sector, from EVs to energy storage systems, electrical busbars are the critical pathways for power transmission. Among them, copper busbars are widely used for their excellent conductivity and mechanical strength. However, overcurrent at the joint interfaces remains a hidden risk that threatens system safety and efficiency.
1. Overcurrent at Copper Joints: A Critical Weak Point
(1) Heat Generation & Current-Carrying Limits
According to Joule’s Law (Q = I²Rt), copper joints generate additional heat due to contact resistance. Standards such as GB/T 7251.1 (IEC 61439-1) limit the temperature rise of copper busbar conductors to 105K, capping working temperature at 140°C. Exceeding this threshold risks annealing, reduced strength, insulation degradation, or even fire.
(2) Current Surge Under Complex Conditions
EV battery systems face fluctuating currents—steady at ~200A, but spiking to 600A during fast charging. Using the short-time withstand current formula S = (I/13) × √t, joints must be designed for peak loads. Meanwhile, high temperatures and humidity raise resistance and contact oxidation, further stressing joint performance.
(3) Rising Demands from Industry Trends
Energy storage and EV systems are pushing toward higher power density. Within five years, battery copper busbar current requirements are projected to increase by 30–50%. As demand grows, joint overcurrent tolerance has become a limiting factor in system design and performance.
2. RHI’s Solution: High-Performance Busbars with Reliable Joints
(1) Advanced Welding for Superior Conductivity
With years of expertise in battery connection solutions, RHI specializes in advanced busbar manufacturing. Our facilities feature over 30 polymer welding units and multiple automated lines, supporting everything from standard copper joints to complex copper-aluminum busbars and rigid-flex assemblies.
During welding, we tightly control temperature, pressure, and timing to reduce contact resistance—ensuring reliable conductivity and enhanced current capacity, even in demanding, high-load environments.
Click here to view RHI's automated polymer welding process.
(2) Custom Solutions for Demanding Applications
Our engineering team provides tailored insulated busbar and bare busbar designs based on current, space, and environmental needs. Simulations ensure optimal current-carrying capacity, temperature control, and mechanical strength. For high-load applications, we increase cross-sectional area or use parallel joints; for tight spaces, compact layouts are deployed.
(3) Total Quality Control for Reliable Performance
RHI has established a robust quality control system that spans every stage of production. We start by carefully screening raw copper, using advanced purity and conductivity tests to ensure only high-grade, low-impurity materials are used—any substandard batch is promptly excluded.
Throughout manufacturing, CCD vision systems check each busbar’s size and surface for defects, while high-precision resistance testers provide real-time data on connection resistance. If anomalies occur, alerts are triggered immediately for swift intervention. Prior to shipment, every busbar is subjected to rigorous testing under simulated real-world stresses—such as overcurrent surges, thermal cycling, and accelerated aging—to verify long-term reliability and stable performance.
With advanced manufacturing, customized engineering, and uncompromising quality control, RHI delivers high-performance copper busbars designed to withstand the increasing demands of next-generation energy systems. As overcurrent challenges at busbar joints become more critical, RHI remains committed to being a reliable partner in building safer, more efficient electrical infrastructures for the future.